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Determination of homogentisic acid in human plasma by GC-MS for diagnosis of alkaptonuria (GC-MS를 이용한 혈장 중 호모겐티식산의 분석;알캅톤뇨증의 진단)

  • Thapa, Maheshwor;Yu, Jundong;Lee, Wonjae;Islam, Fokhrul;Yoon, Hye-Ran
    • Analytical Science and Technology
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    • v.28 no.5
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    • pp.323-330
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    • 2015
  • Alkaptonuria, a rare inherited metabolic disease, is characterized by a lack of homogentisate dioxygenase and accumulation of homogentisic acid (HGA), leading to homogentisic aciduria, arthritis, and ochronosis. In this study, a rapid analytical method, without an expensive and tedious solid phase extraction step, was developed to quantify HGA in plasma using GC-MS. HGA-spiked pooled plasma samples were subjected to liquid-liquid extraction (LLE) with ethyl acetate, followed by trimethylsilyl derivatization (TMS) and GC-MS quantification using selected ion monitoring. The formation of TMS derivative of the 1 carboxylic and 2 hydroxyl functional groups was performed by reacting BSTFA (with 10% TMCS) for 5 min at 80 ℃. For selected ion monitoring, quantification and confirmation ions were determined based on specific ions (m/z 384, m/z 341 and m/z 252) of the TMS derivative of HGA. Calibration curves of pooled normal plasma specimens showed a linear relationship in the range of 1-100 ng/µL. The precision and accuracy were within a relative standard deviation (RSD) of 1 to 15% and a bias of -5 to 25%. Recoveries were obtained in the range of 99-125% and 95-115% for intra-day and inter-day assay, respectively, at 2, 20 and 80 ng/µL. The limit of detection (LOD) and limit of quantification (LOQ) were 0.4 ng/µL and 4 ng/µL, respectively. No homogentisic acid was excreted from normal Korean plasma samples. Collectively, the results from the present study suggest that this method could be useful for routine diagnosis and therapeutic monitoring of alkaptonuria patients with excellent sensitivity and rapidity.

An Analysis of the Characteristics of the Civil Complaints Occurred to the Landscape Architecture Project in Apartment Complex (아파트 단지 조경사업에서 발생하는 민원 특성 분석 - 민원의 공공성과 조치용이성 분석을 중심으로 -)

  • Cho, Se-Hwan;Lee, Myeong-Hun;Jo, Hyun-Kil;Kim, In-Ho;An, Seung-Hong;Oh, Jeong-Hak
    • Journal of the Korean Institute of Landscape Architecture
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    • v.41 no.5
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    • pp.78-90
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    • 2013
  • The purpose of this study was to analyze the types and characteristics of public complaints caused by the landscape architecture projects in the case of apartment complex. Furthermore, its purpose was also to propose as the basis data for the minimization of complaints in the course of future landscape architecture projects. To analyze and categorize the apartment complex civil complaints, we collected basic and case study data from LH Corporation, SH Corporation and GICO from 2009 to 2012. We also categorized 672 landscape complaints to 73 categories and conducted a survey from residents and landscape architecture. This Survey is to use IPA can collect character(public-private), handling of civil affair(easy-hard) and analyze typical characters and difference of civil complaint awareness between landscape architecture and residents. First, we were categorized 73 civil complaints by type in 5 categories such as park, green space and street trees, pedestrian road, facilities, and others. Second, the most common landscape complaints appear in green spaces, street trees, facilities, pedestrian roads and park orders. Third, results of the analysis conducted for each item which are publicity and measures the ease. 'Facilities', 'landscape and greenery', 'pedestrian road' and others were commonly appears from residents and professional awareness of the complaints. However, complaints of park appear different awareness between landscape architecture and residents. Fourth, 35 from 73 civil complaints(47.9%) are having high publicity and easy to measure, 25 civil complaints(34.2%) has analyzed to individual and difficult to measure so about the these complaints need to check from the design step so that it is necessary to minimize the problem of additional expense by civil complaints burden and decrease the confidence of residence problem were considered.

Research of Diffusion Bonding of Tungsten/Copper and Their Properties under High Heat Flux

  • Li, Jun;Yang, Jianfeng
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.14-14
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    • 2011
  • W (tungsten)-alloys will be the most promising plasma facing armor materials in highly loaded plasma interactive components of the next step fusion reactors due to its high melting point, high sputtering resistance and low deuterium/tritium retention. The bonding technology of tungsten to Cu alloy was one of the key issues. In this paper, W/CuCrZr diffusion bonding has been performed successfully by inserting pure metal interlay. The joint microstructure, interfacial elements migration and phase composition were analyzed by SEM, EDS, XRD, and the joint shear strength and micro-hardness were investigated. The mock-ups were fabricated successfully with diffusion bonding and the cladding technology respectively, and the high heat flux test and thermal fatigue test were carried out under actively cooling condition. When Ni foil was used for the bonding of tungsten to CuCrZr, two reaction layers, Ni4W and Ni(W) layer, appeared between the tungsten and Ni interlayer with the optimized condition. Even though Ni4W is hard and brittle, and the strength of the joint was oppositely increased (217 MPa) due primarily to extremely small thicknesses (2~3 ${\mu}m$). When Ti foil was selected as the interlayer, the Ti foil diffused quickly with Cu and was transformed into liquid phase at $1,000^{\circ}C$. Almost all of the liquid was extruded out of the interface zone under bonding pressure, and an extremely thin residual layer (1~2 ${\mu}m$) of the liquid phase was retained between the tungsten and CuCrZr, which shear strength exceeded 160 MPa. When Ni/Ti/Ni multiple interlayers were used for bonding of tungsten to CuCrZr, a large number of intermetallic compound ($Ni_4W/NiTi_2/NiTi/Ni_3T$) were formed for the interdiffusion among W, Ni and Ti. Therefore, the shear strength of the joint was low and just about 85 MPa. The residual stresses in the clad samples with flat, arc, rectangle and trapezoid interface were estimated by Finite Element Analysis. The simulation results show that the flat clad sample was subjected maximum residual stress at the edge of the interface, which could be cracked at the edge and propagated along the interface. As for the rectangle and trapezoid interface, the residual stresses of the interface were lower than that of the flat interface, and the interface of the arc clad sample have lowest residual stress and all of the residual stress with arc interface were divided into different grooved zones, so the probabilities of cracking and propagation were lower than other interfaces. The residual stresses of the mock-ups under high heat flux of 10 $MW/m^2$ were estimated by Finite Element Analysis. The tungsten of the flat interfaces was subjected to tensile stresses (positive $S_x$), and the CuCrZr was subjected to compressive stresses (negative $S_x$). If the interface have a little microcrack, the tungsten of joint was more liable to propagate than the CuCrZr due to the brittle of the tungsten. However, when the flat interface was substituted by arc interfaces, the periodical residual stresses in the joining region were either released or formed a stress field prohibiting the growth or nucleation of the interfacial cracks. Thermal fatigue tests were performed on the mock-ups of flat and arc interface under the heat flux of 10 $MW/m^2$ with the cooling water velocity of 10 m/s. After thermal cycle experiments, a large number of microcracks appeared at the tungsten substrate due to large radial tensile stress on the flat mock-up. The defects would largely affect the heat transfer capability and the structure reliability of the mock-up. As for the arc mock-up, even though some microcracks were found at the interface of the regions, all microcracks with arc interface were divided into different arc-grooved zones, so the propagation of microcracks is difficult.

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ANALYSIS OF DIFFERENTIAL GENE EXPRESSION IN NORMAL, CYST AND AMELOBLASTOMA CELLS (정상, 낭종 및 법랑아세포종 세포에서의 유전자 발현 차이 분석)

  • Yang, Cheol-Hee;Baik, Byeong-Ju;Yang, Yeon-Mi;Kim, Jae-Gon
    • Journal of the korean academy of Pediatric Dentistry
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    • v.32 no.1
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    • pp.75-88
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    • 2005
  • Ameloblastoma is the most commonly occurring odontogenic tumor in oral cavity. Although most are benign epithelial neoplasm, they are generally considered to be locally aggressive and destructive, exhibiting a high rate of recurrence. The biological behavior of this neoplasm is a slowly growing, locally invasive tumor without metastasis, therefore malignant neoplasm, changed its histological appearance to carcinoma or showed distant metastasis, is only defined clinically. In this study, we identified the differentially expressed genes(DEGs) in stages under benign or malignant ameloblastoma compared with normal patient using ordered differential display(ODD) reverse transcription(RT)-PCR and $GeneFishing^{TM}$ technology. ODD RT-PCR is rather effective when the investigation of samples containing very small amounts of total RNA must be accomplished. ODD RT-PCR used the means of amplification with anchored T-primer and adaptor specific primer. bearing definite two bases at their 3' ends and so this method could display differential 3'-expressed sequence taqs(ESTs) patterns without using full-length cDNAs. Compared with standard differential display, ODD RT-PCR is more simple and have enough sensitivity to search for molecular markers by comparing gene expression profiles, However, this method required much effort and skill to perform. $GeneFishing^{TM}$ modified from DD-PCR is an improved method for detecting differentially expressed genes in two or more related samples. This two step RT-PCR method uses a constant reverse primer(anchor ACP-T) to prime the RT reaction and arbitrary primer pairs(annealing control primers, ACPs) during PCR. Because of high annealing specificity of ACPs than ODD RT-PCR, the application of $GeneFishing^{TM}$ to DEG discovery generates reproducible, authentic, and long(100bp to 2kb) PCR products that are detectable on agarose gels. Consequently, various DEGs observed differential expression levels on agarose gels were isolated from normal, benign, and malignant tissues using these methods. The expression patterns of the some isolated DEGs through ODD RT-PCR and $GeneFishing^{TM}$ were confirmed by Northern blot analysis and RT-PCR. The results showed that these identified DEGs were implicated in ameloblastoma neoplasm processes. Therefore, the identified DEGs will be further studied in order to be applied in candidate selection for marker as an early diagnosis during ameloblastoma neoplasm processes.

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Trend Analysis of Strategic Factors to Promote the Image of Cities (도시별 이미지 전략 요인의 경향 분석)

  • Byeon, Jae-Sang
    • Journal of the Korean Institute of Landscape Architecture
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    • v.36 no.2
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    • pp.80-98
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    • 2008
  • In the past, the purpose of urban landscape planning was to beautify cities. Now, that is changing as cities with their own characteristic identities and images are focusing on the making of livable cities. The subject of international competition is turning from a country objective to that of individual cities. To increase the attraction of the urban image will, therefore, be the most important and urgent policy in all cities. A city without global competitiveness will be demoted to a sub-city. This study intends to suggest strategic ways to improve the urban image suitable for Korean cities by the analysis and classification of the advanced cases in other countries. This study can be summarized as follows: 1. The image of cities is promoted by diverse strategies such as establishing landmarks, making meaningful places, hosting festivals and sports events, and making cultural policies. These strategies can be classified by three factors: the landscape and ecological factor, the historical and cultural factor, and the administrative and economic factor. 2. Korean cities are making efforts to promote their images through a variety of ways. Mega cities in Korea are steadily carrying out projects to use the administrative and economic factor such as expanding the infrastructure, supporting enterprises, advertising and marketing with accumulated capital. However, local small cities mainly depend on festivals and simple events or programs that are of interest but which lack characteristic identity. 3. Cities of advanced western countries are upgrading their images by finding and applying strategic methods to reflect characteristic identity and to keep in step with the changes of the times. On the other hand, cities in Japan try to promote urban image with traditional native festivals and with the making of livable places based on resident participation. The central government in Korea needs to establish a master plan considering the regional balance to improve the image of each city. Local governments should carry out these diverse strategic methods. The task after benchmarking advanced cities with beautiful landscapes will be to find an 'All-Korean Style' and apply it to cities with characteristic image.

A Study on Cognition about 119 Rescue·First Aid Team - Gwangju Area College Student as the Central Figure - (119구조·구급대에 대한 인식도 조사 연구 - 광주지역 보건계열과 비보건계열 대학생을 중심으로 -)

  • Kim, Kab-Sun
    • The Korean Journal of Emergency Medical Services
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    • v.6 no.1
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    • pp.141-152
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    • 2002
  • The purpose of this study is to provide the basic materials for searching the way of improvement to heighten the emergency medical welfare level by one step further. To achieve this purpose, the subjects of this study were selected 452 college students in Gwangju, using a random sampling method. The statistical analysis methods utilized for analyzing the collected data are frequency analysis, $x^2$ test. The conclusions obtained from these analyses are as following ; 1. In question about necessary optimum number of persons for rescue first aid activity, health and non-health major college students responded by 39.2%, 45.3% respectively that rescue team 15 people, first aid team 3 people is most suitable. But there was no significant difference in major department(p<0.05). 2. In question about security of the public health doctor and the emergency medical technician, all health and non-health major college students are recognizing necessity urgently, but there was no significant difference in major department(p<0.05). 3. In question about 119 rescue first aid team member applying for an examination qualification grant to the department of EMT's graduate, all health and non-health major college students were highest by 52.9%, 52.4% respectively in "necessity" item. But there was no significant difference in major department(p<0.05). 4. Because rescue first aid equipment level appears higher than 41.7% in non-health major college student's case by 54.2% in health major college student's case, health major college students are recognizing that equipment level should be supplemented more but there was no significant difference in major department(p<0.05). 5. In question about equipment supplement, all health and non-health major college students appeared highest by 64.8%, 69.3% in accident type different special equipment. But there was no significant difference in major department(p<0.05). 6. In question about rescue ambulance car size, we could know being thinking that health and non-health major college student each 61.2%, 56.5% is small and narrow that large size of the rescue ambulance amount need. But there was no significant difference in major department(p<0.05). 7. In question about patient's state is worsened, because rescue first aid equipment is inferior, health major college student responded sometimes 55.1%, many 29.5%. very many by 11.5%, while non-health major college student responded 65.8%, 23.1%, 4.0% respectively. There was significant difference in major department(p<0.05). 8. In question about emergency patient must utilize for 119 rescue ambulance car, all health and non-health major college students appeared highest by 38.8%, 41.3% in "not so" item. In question about rescue first aid team's first-aid treatment ability improves more, all health and non-health major college students appeared highest by 58.1% and 58.7% respectively in "improve" item. In question about "119 rescue ambulance car must go more rapidly than now", all health and non-health major college students are recognizing that should be quicker by 58.1%, 60.9% respectively. When called to 119 all health and non-health major college students responded highest by 55.5%, 53.3% respectively that we must receive first-aid treatment direction from a doctor. In question about "119 rescue ambulance car must be made the pay system", all health and non-health major college students responded 74%, 80% respectively in "not so" item. There was significant difference in major department(p<0.05). In conclusions, In oder to provide superior rescue first aid service to people, a public health doctor should be placed in the situation room inside the fire station so that the doctor could instruct the proper emergency treatment suitable for each situation to the rescue first aid team. Also, national education about a first-aid treatment that do to all people is necessarily necessary in emergency delivery system and this should be spread extensively through school education and broadcasting medium and education should be gone side by side, and see that will can save emergency patients' life which is more when these education consists continuously fixed period for public institution of policeman, fire officer etc. specially. And for reinforcement of patient transfer system, public organization must procure special ambulance car so that emergency patient receive first aid treatment while transfer.

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A Study on the Relationship Between the Performance of Venture Business and CEO's Characteristics (벤처기업 경영자 특성이 경영성과에 미치는 영향에 관한 연구;대덕연구개발특구를 중심으로)

  • Yoon, Bo-Hyun;Park, Joon-Byoung
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.2 no.3
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    • pp.145-168
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    • 2007
  • Current researches have been proceed on CEO's Characteristics of venture business because the CEO has considered as one of the important factors for the success of venture business. But prior research on the performance of venture business has produced inconsistently in terms of CEO's characteristics. The purpose of this study is to develop a comprehensive model for the relation between the performance and a type of CEO's characteristics by a growth process of venture business, which is the main subject of analysis in venture business. Also, this study analyzes various CEO's characteristics and the effects for performance of venture business which are in the Daedeok valley. To achieve the purpose of this research, an empirical study by using research model and hypotheses including the general characteristics of venture business and CEO's demographic characteristics has been presented as a research method for relation analysis. The principal findings of the research and its significance are summarized as follows: First, it was found that there is a significant different in the performance of CEO's behavioral characteristics by the scale, type and growing step of organization for venture business. Second, it was found that there is not a significant between an academic career, management experience, foundation experience for business and related working experience of venture CEO and the performance, but there os a partially significant difference in CEO's behavioral characteristics. Third, it was found that there is a partially significant difference between CEO's behavioral characteristics of venture business and the performance by the general characteristics of organization for venture business and demographic characteristics. In conclusion, in spite of the insufficient research for venture business in Daedeok, the implications of theses findings and contributions made by this research is to confirm the characteristics factor of CEO for venture business and general characteristics of organization for venture business by multidisciplinary side. In addition, the findings provide the basis for the analyzing of managerial strong point and weak point referred to supporting system for venture business. Finally, the findings of this study suggest that the results should be a useful data for groping a solution for upbringing plans in terms of a long-term point of view.

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3-Dimensional Verification Technique for Target Point Error (자기공명영상기반 겔 선량측정법을 이용한 3차원적 목표 중심점 점검기술)

  • Lee, Kyung-Nam;Lee, Dong-Joon;Suh, Tae-Suk
    • Progress in Medical Physics
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    • v.22 no.1
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    • pp.35-41
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    • 2011
  • For overall system test, hidden-target test have been used using film which leads to inherent analysis error. The purpose of our study is to quantify this error and to propose gel dosimeter based verification technique for 3-dimensional target point error. The phantom was made for simulation of human head and this has ability to equip 10 gel-dosimeter. $BANGkit^{TM}$ which we are able to manufacture whenever it is needed as well as to easily change the container with different shapes was used as a gel dosimeter. The 10 targets were divided into two groups based on shapes of areas with a planned 50% isodose line. All treatment and analysis was performed three times using Novalis and $BrainSCAN^{TM}$. The target point error is $0.77{\pm}0.15mm$ for 10 targets and directional target point error in each direction is $0.54{\pm}0.23mm$, $0.37{\pm}0.08mm$, $0.33{\pm}0.10mm$ in AP (anterior-posterior), LAT (lateral), and VERT (vertical) direction, respectively. The result of less than 1 mm shows that the treatment was performed through each precise step in treatment procedure. In conclusion, the 3-dimensional target point verification technique can be one of the techniques for overall system test.

Molecular Characterization of Cinnamate 4-Hydroxylase gene in Red Hot Pepper (Capsicum annuum L.) (고추에서 분리한 Cinnamate 4-Hydroxylase 유전자의 분자생물학적 특성)

  • Kim Kye-Won;Ha Sun-Hwa;Cho Kang-Jin;Kim Eun-Ju;Lee Min-Kyung;Yu Jae-Ju;Kim Jong-Guk;Lee Shin-Woo
    • Journal of Plant Biotechnology
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    • v.32 no.3
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    • pp.167-173
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    • 2005
  • Three different cDNAS for cinnamate 4-hydroxylase (C4H) which are involved in the second step of the general phenylpropanoid pathway were isolated and designated as pc4h1 (1,755 bp), pc4h2 (1,655 bp), and pc4h3 (1,316 bp), respectively. The nucleotide sequence analysis revealed that both pc4h1 and pc4h2 clones encode polypeptides of 505 amino acids frame but pc4h3 clone was truncated at the 5'-end of coding region. The alignment of the deduced amino acid sequences showed that PC4H1 and PC4H2 are highly homologous (95.8% identical) with each other and contain three conserved domains which are typical in cytochrome P450 monooxygenase: proline-rich region, threonine-containing binding pocket for the oxygen molecule, and heme binding region. In addition, result of the phylogenic tree analysis revealed that both pepper C4Hs belong to Class 1. pc4h2 transcription was strongly induced in wounded fruit (400%) and root (200%) relative to its very low basal level but not in leaf or stem tissue. In case of pc4h1, the basal level of transcription was higher than pc4h2 but induction by wounding was lower in fruit and root while leaf and stem tissues did not respond to wounding. The basal level of pc4h3 transcripts was not, if any, detectable and response to wounding was not observed.

An Examination of Knowledge Sourcing Strategies Effects on Corporate Performance in Small Enterprises (소규모 기업에 있어서 지식소싱 전략이 기업성과에 미치는 영향 고찰)

  • Choi, Byoung-Gu
    • Asia pacific journal of information systems
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    • v.18 no.4
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    • pp.57-81
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    • 2008
  • Knowledge is an essential strategic weapon for sustaining competitive advantage and is the key determinant for organizational growth. When knowledge is shared and disseminated throughout the organization, it increases an organization's value by providing the ability to respond to new and unusual situations. The growing importance of knowledge as a critical resource has forced executives to pay attention to their organizational knowledge. Organizations are increasingly undertaking knowledge management initiatives and making significant investments. Knowledge sourcing is considered as the first important step in effective knowledge management. Most firms continue to make an effort to realize the benefits of knowledge management by using various knowledge sources effectively. Appropriate knowledge sourcing strategies enable organizations to create, acquire, and access knowledge in a timely manner by reducing search and transfer costs, which result in better firm performance. In response, the knowledge management literature has devoted substantial attention to the analysis of knowledge sourcing strategies. Many studies have categorized knowledge sourcing strategies into intemal- and external-oriented. Internal-oriented sourcing strategy attempts to increase firm performance by integrating knowledge within the boundary of the firm. On the contrary, external-oriented strategy attempts to bring knowledge in from outside sources via either acquisition or imitation, and then to transfer that knowledge across to the organization. However, the extant literature on knowledge sourcing strategies focuses primarily on large organizations. Although many studies have clearly highlighted major differences between large and small firms and the need to adopt different strategies for different firm sizes, scant attention has been given to analyzing how knowledge sourcing strategies affect firm performance in small firms and what are the differences between small and large firms in the patterns of knowledge sourcing strategies adoption. This study attempts to advance the current literature by examining the impact of knowledge sourcing strategies on small firm performance from a holistic perspective. By drawing on knowledge based theory from organization science and complementarity theory from the economics literature, this paper is motivated by the following questions: (1) what are the adoption patterns of different knowledge sourcing strategies in small firms (i,e., what sourcing strategies should be adopted and which sourcing strategies work well together in small firms)?; and (2) what are the performance implications of these adoption patterns? In order to answer the questions, this study developed three hypotheses. First hypothesis based on knowledge based theory is that internal-oriented knowledge sourcing is positively associated with small firm performance. Second hypothesis developed on the basis of knowledge based theory is that external-oriented knowledge sourcing is positively associated with small firm performance. The third one based on complementarity theory is that pursuing both internal- and external-oriented knowledge sourcing simultaneously is negatively or less positively associated with small firm performance. As a sampling frame, 700 firms were identified from the Annual Corporation Report in Korea. Survey questionnaires were mailed to owners or executives who were most erudite about the firm s knowledge sourcing strategies and performance. A total of 188 companies replied, yielding a response rate of 26.8%. Due to incomplete data, 12 responses were eliminated, leaving 176 responses for the final analysis. Since all independent variables were measured using continuous variables, supermodularity function was used to test the hypotheses based on the cross partial derivative of payoff function. The results indicated no significant impact of internal-oriented sourcing strategies while positive impact of external-oriented sourcing strategy on small firm performance. This intriguing result could be explained on the basis of various resource and capital constraints of small firms. Small firms typically have restricted financial and human resources. They do not have enough assets to always develop knowledge internally. Another possible explanation is competency traps or core rigidities. Building up a knowledge base based on internal knowledge creates core competences, but at the same time, excessive internal focused knowledge exploration leads to behaviors blind to other knowledge. Interestingly, this study found that Internal- and external-oriented knowledge sourcing strategies had a substitutive relationship, which was inconsistent with previous studies that suggested complementary relationship between them. This result might be explained using organizational identification theory. Internal organizational members may perceive external knowledge as a threat, and tend to ignore knowledge from external sources because they prefer to maintain their own knowledge, legitimacy, and homogeneous attitudes. Therefore, integrating knowledge from internal and external sources might not be effective, resulting in failure of improvements of firm performance. Another possible explanation is small firms resource and capital constraints and lack of management expertise and absorptive capacity. Although the integration of different knowledge sources is critical, high levels of knowledge sourcing in many areas are quite expensive and so are often unrealistic for small enterprises. This study provides several implications for research as well as practice. First this study extends the existing knowledge by examining the substitutability (and complementarity) of knowledge sourcing strategies. Most prior studies have tended to investigate the independent effects of these strategies on performance without considering their combined impacts. Furthermore, this study tests complementarity based on the productivity approach that has been considered as a definitive test method for complementarity. Second, this study sheds new light on knowledge management research by identifying the relationship between knowledge sourcing strategies and small firm performance. Most current literature has insisted complementary relationship between knowledge sourcing strategies on the basis of data from large firms. Contrary to the conventional wisdom, this study identifies substitutive relationship between knowledge sourcing strategies using data from small firms. Third, implications for practice highlight that managers of small firms should focus on knowledge sourcing from external-oriented strategies. Moreover, adoption of both sourcing strategies simultaneousiy impedes small firm performance.